In June, the state issued the Clean Energy Industry Report, which projected 12 percent growth in jobs in the clean energy sector. Recently, Gov. Peter Shumlin touted the installation of cold-climate heat pumps in the region for their efficiency and the fact they are powered by “clean energy,” meaning electricity.

Clean energy is an idea that most Vermonters would support, but its very definition will vary greatly depending upon which industry, interest group or governmental agency you ask.

At the federal level, the Environmental Protection Agency doesn’t offer a specific definition, but does say it includes “energy efficiency and clean energy supply options like highly efficient combined heat and power as well as renewable energy sources.”

By this metric, the EPA considers the burning of municipal solid waste as a clean method of generating electricity, because humans continue to generate trash, making it a renewable resource. The fact that emissions can vary widely depending upon what is being burned does not preclude this method from being considered clean.

At the other end of the spectrum is the perspective that clean energy must take into account the amount of carbon — and other elements considered detrimental to the atmosphere, such as sulfur — being emitted into the air.

“Clean energy is energy that reduces our dependence on fossil fuels in a sustainable way and reduces our impact on the climate,” said Ben Walsh, clean energy advocate for the Vermont Public Interest Research Group (VPIRG).

In 2012, the federal Clean Energy Standard Act — which died in committee — tried to define clean energy to include nearly every form of electricity generation, provided it emitted less carbon than coal.

“That definition is an incredibly low bar,” Walsh said. “As a society, we need to do a lot better than that.”

Chris Recchia, commissioner for the Public Service Department, shared the state’s view on what constitutes clean energy.

“For us, it means, generally, renewable resources that are within the state’s ability to ensure they are environmentally sound,” he said. “Vermont needs to use the resources we have available, which, thankfully, don’t include oil, gas or coal.”

Renewable resources, in this case, can mean solar and wind, as well as those that emit carbon such as biomass and biofuels. It’s a position shared by Renewable Energy Vermont, a consortium of colleges, individuals and businesses with the stated goal of reducing the use of fossil fuels and encouraging renewable power sources.

“It really depends on the efficiency of the technology you are using and the efficiency of the power source,” said Gabrielle Stebbins, executive director of Renewable Energy Vermont. “With today’s technology, biomass can be pretty close to clean.”

And for some interests, being close to clean, or at least cleaner than the competition, is enough to call a technology clean. Vermont Gas Systems, which provides natural gas for heating purposes — and in a few cases, to power vehicles — uses the tag line “Clean energy. Clean air.”

“People have raised concerns about fracking, but even with fracking, natural gas is 23 percent more efficient than oil,” said Steve Wark, director of communications for Vermont Gas Systems, who noted gas also burns cleaner than propane or wood.

Wark also argued that even renewable energy can contribute carbon to the atmosphere.

“Even solar has an impact,” Wark said. “If the panels are being made in China, they’re being built using some of the dirtiest electricity generated on the planet.”

Walsh was skeptical of claims that natural gas is a clean source of energy.

“At the end of the day, I don’t think you’re going to fool Vermonters into thinking that fossil fuels are good and renewables are not,” Walsh said. “Even the worst renewable is better than the best fossil fuel.”

“When an energy producer says they are clean or green, you should be skeptical,” said Kevin Jones, deputy director of the Institute for Energy and the Environment at Vermont Law School.

He noted the proliferation of large-scale solar projects in the state. While this might sound good, Jones said, the energy generated from these projects are not used by Vermonters, but are sold to out-of-state electricity producers in the form of renewable energy credits.

“The governor might go and cut a ribbon at a solar facility, but the reality is that producer is selling, lawfully, green energy subsidized by the state to out-of-state markets,” Jones said. “These local solar projects are not reducing the carbon footprint of the state.”

Recchia said the sale of renewable energy credits is necessary at this point.

“We have created an industry where we are number one for solar jobs and clean energy per capita, but that doesn’t mean we are immediately reaping the benefits,” Recchia said.

“We get the benefit of getting the projects off the ground, and will take advantage using renewable energy in the future,” he said, noting the state has a goal of getting 90 percent of its power from renewable energy by 2050.

Green Mountain Power, which claims to have the cleanest energy portfolio of any state in the region, uses a combination of nuclear power and fossil fuels to complement the 47 percent of its power it receives from hydro power, a “clean” source of power that is also criticized for its negative effects upon fish habitats.

“There are pros and cons to every way you generate electricity,” said GMP spokeswoman Dorothy Schnure. “There are environmental impacts to every power source.”

Wark said the transition to renewable energy will be gradual, and will include fossil fuels.

“All of these fuel sources are going to be needed for the foreseeable future,” Wark said “We can’t just flip a switch. There’s going to be a transition, and that transition will be based on policy and science.”